Iwaki, Japan climate
Cfa Humid subtropical
Iwaki has a seasonal mild-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is August with an average daily high near 82°F, while the coldest is January averaging around 32°F at night. Around 57 inches of precipitation falls each year, peaking in October (7.6 inches) and easing off in December (2.0 inches).
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Summers
Warm
Highs near 82°F in August.
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Winters
Cold
Lows near 32°F in January.
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Rain
Wet
About 57 in of rain a year.
Wettest in October
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Sky & trend
Often cloudy
Cloudy skies much of the year.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresHours of sunshine per day
Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)Iwaki climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 47 | 48 | 53 | 60 | 67 | 73 | 78 | 82 | 78 | 70 | 61 | 52 |
| Avg temp (°F) | 39 | 40 | 45 | 53 | 60 | 66 | 73 | 76 | 72 | 62 | 53 | 44 |
| Avg low (°F) | 32 | 32 | 37 | 45 | 54 | 62 | 68 | 72 | 66 | 56 | 45 | 36 |
| Precipitation (in) | 2.3 | 2.1 | 4.3 | 4.9 | 5.8 | 5.9 | 6.3 | 4.8 | 7.6 | 7.6 | 3.2 | 2.0 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 47 | 48 | 53 | 60 | 67 | 73 |
| Avg temp (°F) | 39 | 40 | 45 | 53 | 60 | 66 |
| Avg low (°F) | 32 | 32 | 37 | 45 | 54 | 62 |
| Precipitation (in) | 2.3 | 2.1 | 4.3 | 4.9 | 5.8 | 5.9 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 78 | 82 | 78 | 70 | 61 | 52 |
| Avg temp (°F) | 73 | 76 | 72 | 62 | 53 | 44 |
| Avg low (°F) | 68 | 72 | 66 | 56 | 45 | 36 |
| Precipitation (in) | 6.3 | 4.8 | 7.6 | 7.6 | 3.2 | 2.0 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 58 | 62 | 65 | 66 | 70 | 80 | 78 | 68 | 74 | 69 | 62 | 57 |
| Relative humidity (%) | 85 | 82 | 80 | 79 | 81 | 84 | 85 | 85 | 86 | 86 | 86 | 86 |
| Wind speed (mph) | 2.0 | 2.3 | 2.1 | 1.7 | 1.1 | 0.8 | 0.7 | 0.8 | 1.0 | 1.2 | 1.3 | 1.7 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 58 | 62 | 65 | 66 | 70 | 80 |
| Relative humidity (%) | 85 | 82 | 80 | 79 | 81 | 84 |
| Wind speed (mph) | 2.0 | 2.3 | 2.1 | 1.7 | 1.1 | 0.8 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 78 | 68 | 74 | 69 | 62 | 57 |
| Relative humidity (%) | 85 | 85 | 86 | 86 | 86 | 86 |
| Wind speed (mph) | 0.7 | 0.8 | 1.0 | 1.2 | 1.3 | 1.7 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from the Japan Meteorological Agency, measured at Onahama, about 12 km from the city centre.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.